The genome of the budding yeast Saccharomyces cerevisiae has been sequenced. This yeast provides a powerful genetic and molecular system. Here, we propose to create a facility for the production and use of S. Cerevisiae spotted DNA micro arrays. These micro arrays would be made principally for thee community of nine yeast laboratories at the State University of New York, Stony Brook, and, if resources permit, to scientist elsewhere in the United States. The facility would manufacture micro arrays, and would provide a database, software, and expertise for the analysis of data. Outside users of the facility would do experiments designed for micro array analysis, make RNA, validate the RNA samples, and convert the RNA to labeled DNA. This labeled c DNA would be sent to the facility, where it wold be hybridized to the micro arrays, scanned, and subjected to standard forms of analysis. Results would be posted to a Web site for further analysis by users. Resources for more extensive data analysis would be available on the facility's Web site. The operation of the facility would be supported by user charges of about $75 per array experiment.